Jerry Schippa

@jerryschippa.bsky.social

Traffic Engineer. Posts mostly about 🚦, 🚌, & 🎲.

There's a trend in intersection design it seems that puts a median between left turns and thru movements, and sometimes offsets the left turns so there is a small or no median between them and the opposing thru traffic. It's an evolution of the positive offset left turn. But is it good?

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The default North American traffic signal operation seems to be to do as much as possible to not stop "mainline" phases regardless if traffic is there or not. Over-use of coordination, long delays on detectors, over-reliance on permissive turns.

We waited 76" to get our green crossing WB at Anderson & Wright. Not even the longest wait. Counting all NBLT, NB, SB, and EBLT (all conflicting phases) guess how many total vehicles went by? 32.

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Lessons learned from BRT...it is an iterative process that you simply cant throw money at once and say "I have TSP now". Much like every traffic signal system. Also, I cant shut up about TSP.

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I think terrace trees should take far more priority than median trees, even if that means mature trees get removed. Ped/bike comfort needs to be more important than aesthetics. We end up living with these designs for 40+ years. That's is my street design/climate disaster hot take.

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The power of phase insertion! The bus phase will always be the next phase with this sequence! My favorite TSP strategy when you have to make a protected/exclusive movement is phase insertion!

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